Carbon Capture Options For Gas Processing Facilities

Abstract For operators of gas processing facilities seeking to decarbonise their operations through carbon capture, one significant challenge stands out: identifying the optimal point within the processing line-up for recovering a high-purity CO2 stream suitable for sequestration. By conducting a comprehensive techno-economic assessment of principal capture points within the gas processing line-up, this paper aims to provide valuable insights to address this specific challenge. In this study, we will evaluate capturing CO2 (pre or post combustion) from various points within a standard natural gas treating line-up consisting of an acid gas removal unit (AGRU), acid gas enrichment unit (AGEU), sulphur recovery unit (SRU), tail gas treating unit (TGTU), and incinerator. Real-world scenarios encountered by Shell Catalysts & Technologies’ customers inform our assessment, drawing upon simulations and designs developed by our team. For instance, recent projects like the one at Abu Dhabi National Oil Company, capturing CO2 post combustion from the TGTU, contribute valuable insights to our analysis. The paper will conclude that the optimal location varies according to a wide range of factors, including the composition of the feed gas, particularly the levels of sulphur, and plant-specific requirements such as sulphur recovery efficiency and environmental regulations. Crucially, we will also provide insights into the circumstances favouring each capture point. For example, the AGRU is advantaged for high-pressure CO2 capture, contingent upon very low sulphur content in the feed gas. However, there are circumstances in which the AGEU, with the right solvent, could be more effective, especially as it could achieve the twin purpose of preparing acid gas that is suitable for the SRU and generating a CO2 stream fit for sequestration. Such insights are crucial for operators seeking to implement an effective carbon capture project. Carbon capture at gas processing facilities is relatively new, and uncertainty prevails in pinpointing the optimal location for CO2 capture. By tackling this challenge, this paper offers valuable, practical guidance for operators navigating the complexities of decarbonising gas processing facilities. It contributes to the evolving understanding of carbon capture technologies, facilitating more informed decision-making within the energy industry.